1. Field of the Invention
The present invention relates to an injection molding apparatus for producing plastic products having grain patterns thereon.
2. Background Art
Conventionally, plastic products having grained surfaces have been produced by preparing a laminate material with a grain pattern on its surface in advance, and then the laminate material is adhered using an adhesive or the like to the surface of the plastic product. However, when there are three-dimensional curved surfaces or the like on the products, this method has a problem in that the laminate material is stretched unnecessarily or that wrinkles occur around the curved surfaces. There is also a problem in that there is stretching or sagging in the grain pattern itself.
In order to solve these problems, a method for producing a plastic product having a grained surface has been proposed. According to this method, a grain pattern is formed in advance in one die, and a laminate material for creating the grain pattern is placed in this die. Under this condition, a plastic product formed in a predetermined shape and coated with adhesive is pushed against the back surface of the laminate material such that the laminate material is caused to adhere to the product. Thereafter, the laminate material is pulled by a vacuum from the die having the grain pattern thereon. However, this grained pattern fabrication process has a problem in that it takes too long.
In general, in one aspect, the present invention relates to an injection molding apparatus for producing a plastic product having a grain pattern thereon. The apparatus comprises a female die having a grain pattern on an inner surface thereof, the female die further provided with a vacuum drawing mechanism for drawing a vacuum therethrough, and a male die having an injection aperture for injecting a thermal formable plastic material therethrough. The male die comprises a burr cutter adapted to slide fit in a gap between the male die and the female die and a guide pin with a spacer provided at four corners of the male die for controlling a distance between the male die and a female die.
Other aspects and advantages of the invention will be apparent from the following description and the appended claims.